@@ -1,10 +1,11 @@
 #define FUSE_USE_VERSION 26
 
 #include <sys/fsuid.h>
 #include <sys/types.h>
 #include <pthread.h>
+#include <signal.h>
 #include <string.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <unistd.h>
 #include <errno.h>
@@ -51,10 +52,15 @@
  */
 pthread_mutex_t appfs_path_info_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
 int appfs_path_info_cache_size = 8209;
 struct appfs_pathinfo *appfs_path_info_cache = NULL;
 
+/*
+ * Global variables for AppFS Tcl Interpreter restarting
+ */
+int interp_reset_key = 0;
+
 /*
  * AppFS Path Type:  Describes the type of path a given file is
  */
 typedef enum {
 	APPFS_PATHTYPE_INVALID,
@@ -248,12 +254,21 @@
  * Return the thread-specific Tcl interpreter, creating it if needed
  */
 static Tcl_Interp *appfs_TclInterp(void) {
 	Tcl_Interp *interp;
 	int pthread_ret;
+	static __thread int thread_interp_reset_key = 0;
 
 	interp = pthread_getspecific(interpKey);
+	if (interp != NULL && thread_interp_reset_key != interp_reset_key) {
+		APPFS_DEBUG("Terminating old interpreter and restarting due to reset request.");
+
+		Tcl_DeleteInterp(interp);
+
+		interp = NULL;
+	}
+
 	if (interp == NULL) {
 		interp = appfs_create_TclInterp(NULL);
 
 		if (interp == NULL) {
 			return(NULL);
@@ -309,10 +324,21 @@
 		APPFS_DEBUG("Tcl command failed, ::errorInfo contains: %s\n", Tcl_GetVar(interp, "::errorInfo", 0));
 	}
 
 	return(retval);
 }
+
+/*
+ * Request all Tcl interpreters restart
+ */
+static void appfs_tcl_ResetInterps(void) {
+	APPFS_DEBUG("Requesting reset of all interpreters.");
+
+	__sync_add_and_fetch(&interp_reset_key, 1);
+
+	return;
+}
 
 /*
  * Determine the UID for the user making the current FUSE filesystem request.
  * This will be used to lookup the user's home directory so we can search for
  * locally modified files.
@@ -555,10 +581,12 @@
 }
 
 static void appfs_get_path_info_cache_flush(uid_t uid, int new_size) {
 	unsigned int idx;
 	int pthread_ret;
+
+	APPFS_DEBUG("Flushing AppFS cache (uid = %lli, new_size = %i)", (long long) uid, new_size);
 
 	pthread_ret = pthread_mutex_lock(&appfs_path_info_cache_mutex);
 	if (pthread_ret != 0) {
 		APPFS_DEBUG("Unable to lock path_info cache mutex !");
 
@@ -1429,10 +1457,37 @@
 
 	Tcl_PkgProvide(interp, "appfsd", "1.0");
 
 	return(TCL_OK);
 }
+
+/*
+ * Hot-restart support
+ */
+/* Initiate a hot-restart */
+static void appfs_hot_restart(void) {
+	appfs_tcl_ResetInterps();
+	appfs_get_path_info_cache_flush(-1, -1);
+
+	return;
+}
+
+/*
+ * Signal handler to initiate a hot-restart
+ */
+static void appfs_signal_handler(int sig) {
+	/* Do not handle signals until FUSE has been started */
+	if (!appfs_fuse_started) {
+		return;
+	}
+
+	if (sig == SIGHUP) {
+		appfs_hot_restart();
+	}
+
+	return;
+}
 
 /*
  * FUSE operations structure
  */
 static struct fuse_operations appfs_operations = {
@@ -1475,10 +1530,11 @@
 int main(int argc, char **argv) {
 	Tcl_Interp *test_interp;
 	char *test_interp_error;
 	struct fuse_args args = FUSE_ARGS_INIT(argc, argv);
 	int pthread_ret;
+	void *signal_ret;
 
 	/*
 	 * Skip passed program name
 	 */
 	if (argc == 0 || argv == NULL) {
@@ -1561,10 +1617,19 @@
 		fprintf(stderr, "%s\n", test_interp_error);
 
 		return(1);
 	}
 	Tcl_DeleteInterp(test_interp);
+
+	/*
+	 * Register a signal handler for hot-restart requests
+	 */
+	signal_ret = signal(SIGHUP, appfs_signal_handler);
+	if (signal_ret == SIG_ERR) {
+		fprintf(stderr, "Unable to install signal handler for hot-restart\n");
+		fprintf(stderr, "Hot-restart will not be available.\n");
+	}
 
 	/*
 	 * Add FUSE arguments which we always supply
 	 */
 	fuse_opt_parse(&args, NULL, NULL, appfs_fuse_opt_cb);